This is the process I used for my most valued seeds that I did not expect to germinate readily.

His photo shows fully hydrated seeds being prepared for stratification in perlite. I switched from vermiculite to perlite because it is easier to monitor the progress of chemical leaching and replace the perlite as needed. On the left, the dish has been approximately half-filled with moist perlite and the seeds spread over it. The container on the right has pre-moistened perlite that will be used to cover the seeds so that they are 1/2 to 1" beneath the surface.

The label shows not only the cross but the number of seeds in the dish. The plastic wrap is held in place by a rubber band so the seal is not air-tight but holds moisture reasonably well. If a thin film of water can be seen on the underside of the wrap, the moisture level is good. If the plastic is completely dry the perlite needs to be remoistened. If water drops are forming, it's too wet but can be dried out by simply removing the cover for a while. "A while" varies, of course, with ambient conditions.